Answer:
19.3 g/cm3
Explanation:
A 10.0 cm3 sample of copper has a mass of 89.6 g. What is the density of copper? 19.3 g/cm3.
According to the following reaction, how many grams of hydrofluoric acid will be formed upon the complete reaction of 25.6 grams of water with excess silicon tetrafluoride?
silicon tetrafluoride (s) + water (l) → hydrofluoric acid (aq) + silicon dioxide (s)
Answer:
56.89 g of HF
Explanation:
We'll begin by writing the balance equation for the reaction. This is illustrated below:
SiF₄ + 2H₂O —> 4HF + SiO₂
Next, we shall determine the mass of H₂O that reacted and the mass of HF produced from the balanced equation.
This is illustrated:
Molar mass of H₂O = (2×1) + 16 = 2 + 16 = 18 g/mol
Mass of H₂O from the balanced equation = 2 × 18 = 36 g
Molar mass of HF = 1 + 19 = 20 g/mol
Mass of HF from the balanced equation = 4 × 20 = 80 g
Summary:
From the balanced equation above,
36 g of H₂O reacted to produce 80 g of HF.
Finally, we shall determine the mass of HF produced from the reaction. This is illustrated below:
From the balanced equation above,
36 g of H₂O reacted to produce 80 g of HF.
Therefore, 25.6 g of H₂O will react to produce = (25.6 × 80)/36 = 56.89 g of HF.
Thus, 56.89 g of HF were produced from the reaction.
The amount of UVA radiation hitting a surface at sea level in a lightly clouded day is about 70W/m2. About half of that can be absorbed by the skin. A typical carbon- carbon bond requires 348 kJ/mol to break. A person lies on the beach for about 1 hour without sunscreen (i.e. fully exposed to UVA radiation). Estimate the number of C-C bonds broken in this person’s back (about 0.18 m2) over that period. Assume that the average wavelength of UVA is 335 nm.
Answer:
Explanation:
Area of person's back = .18 m²
energy of radiation falling on the back per second
= 70 x .18 J
= 12.6J
Energy absorbed per second = .5 x 12.6 = 6.3 J
energy absorbed per hour = 6.3 x 60 x 60 = 22680 J
energy required to break one mole bond = 348 x 10³ J
energy required to break one bond = 348 x 10³ / 6.02 x 10²³
= 57.8 x 10⁻²⁰ J .
So number of bonds broken in one hour = 22680 / 57.8 x 10⁻²⁰
= .392 x 10²³ bonds .
= 39.2 x 10²⁰ bonds .
Which of the following is a common sign that a chemical change has occurred?
Answer:
C a chemical has become a different color
Explanation:
is it a chemical change when water turns to ice? or to water vapor? no because it can easily change back.
it's not A obviously
I just explained why it's not B
and again it's obviously not D
It's C because once you change the color of something you can most likely not change it back (cake batter, stained glass) making it a chemical change
Why is a fatty acid called a fatty acid
Answer:
Fatty acids are fairly long linear hydrocarbon chains with a carboxylic acid group at one end. Fatty acids are named based on the number of carbon atoms and carbon-carbon double bonds in the chain. ... This bond could bind a molecule of hydrogen, forming a 16-carbon molecule with no carbon-carbon double bonds.
Explanation:
Fatty acids are the fundamental blocks of fat in our bodies and our meals.
Fatty acids are carboxylic acids with long aliphatic chains that can be branched or unbranched in biochemistry. Natural fatty acids have an even number of carbon atoms and are usually unbranched. Fatty acids are important components of lipids.
They exist as esters in three different forms:
PhospholipidsTriglyceridesCholesteryl estersFatty acids that are vital to our bodies but cannot be produced in sufficient quantities within our cells are obtained from dietary sources. They are referred to as essential fatty acids. Linoleic acid and alpha-linoleic acid are two examples.
Fatty acids serve as energy sources as well as membrane constituents. They are involved in signaling, cell metabolism, and energy storage in adipose tissues.
To know more about Fatty acids,
brainly.com/question/29593274
15
Density of Metals at Room Temperature
Density
Name of Metal
(g/mL)
Nickel
8.90
Copper
8.96
Palladium
12.02
smi Wetes
Silver
10.5
Platinum
21.4
Gold
19.32
Refer to the Density of Metals at Room Temperature table above. How is the density of a
metal related to its location on the Periodic Table?
A
As the metal's atomic number increases, the density increases.
B
As the metal's atomic mass increases, the density increases.
С
As the metal's number of valence electrons increases, the density increases.
D
As the metal's number of electron energy levels increases, the density increases.
Answer:
platinum = 21.4 I think it's letter D to be related to it.
Which of the following reactions will proceed as drawn below? (Yes or No)
Answer:
i wish i could help but t know either so i wish you luck for an answer once again truly sorry don'
Explanation:
i am sorry but i do not know :(
plz help answer both will mark brainest
Nerve Impulses ____.
A. start at the dendrite.
B. are electrical signals.
C. can travel backwards and forwards.
D. are only found in the autonomic nervous system.
Answer:
B. are electrical signals.
Heterotrophic bacteria obtain food by
What stress causes this type of fault to form? O compression O gravity O tension O shearing
Answer: It’s D
Explanation:
Cuz I said so
Answer: d. Shearing
Explanation:
You are trying to confirm that your bottle of hydrochloric acid is supposedly 1.0 M, as labeled. You decided to perform a titration with 1.3 M sodium hydroxide and 100 mL of your hydrochloric acid. You expect to use 77 mL of sodium hydroxide to neutralize the acid, but in the experiment it actually took 89.13 mL of NaOH to reach the endpoint. What is the actual concentration of the hydrochloric acid?
Answer:
The actual concentration of the hydrochloric acid is 1.2M
Explanation:
The formula to be used here is that of concentration (popularly used during titration);
CₐVₐ/CbVb =nₐ/nb
where Cₐ is the concentration of acid (supposed to be 1.0 M but unsure)
Vₐ is the volume of acid (100 ml)
Cb is the concentration of base (1.3 M)
Vb is the volume of base (89.13 ml)
nₐ is the volume of acid
nb is the volume of base
The equation for the reaction described in the question is
HCl + NaOH ⇒ NaCl + H₂O
we can see from the above equation the ratio of the number of moles for both the acid and the base is 1:1
Thus;
Cₐ × 100/1.3 × 89.13 =1/1
Cₐ = 1.3 × 89.13/100
Cₐ = 1.2M
The actual concentration of the hydrochloric acid is 1.2M
During a solar eclipse, which of the following is true?
HELP
Answer:
The moon blocks the Sun's light from hitting the surface of the earth
Explanation:
The number that represents a neutral pH is . (2 points)
Answer:
7
Explanation:
Answer:
7 is your answer
YW! :)
Explanation:
Q12. What thickness (in cm) is the silicon block (density = 2.13 g/cm3) that is 2.65 cm
wide and long necessary to react with 88.3 g of Cr2O3 by the reaction:
Si (s) + Cr203 (s) → SiO2 (s) + Cr (1)
Answer:
1.63cm
Explanation:
Given parameters:
Density of silicon = 2.13g/cm³
Mass of Cr₂O₃ = 88.3g
Width of the block = 2.65cm
Length of the block = 2.65cm
Unknown:
Thickness of the block = ?
Solution:
Reaction equation:
3Si + 2Cr₂O₃ → 3SiO₂ + 4Cr
Let us find the mass of Si,
So,
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
we find the number of moles of Cr₂O₃ ;
Molar mass of Cr₂O₃ = 2(52) + 3(16) = 152g/mol
Number of moles of Cr₂O₃ = [tex]\frac{88.3}{152}[/tex] = 0.58mole
Then;
we know that;
2 moles of Cr₂O₃ reacted with 3 moles of Cr₂O₃
0.58moles of Cr₂O₃ will react with [tex]\frac{0.58 x 3}{2}[/tex] = 0.87mole
So,
Mass of Si = number of moles x molar mass
molar mass of Si = 28g/mol
Mass of Si = 0.87 x 28 = 24.4g
Since density is the mass per unit volume of a compound;
Mass of Si = density of Si x volume of Si block
Volume of Si block = length x width x thickness = 2.65 x 2.65 x thickness
Volume of Si block = 7.02 x thickness
Mass of Si = 2.13 x 7.02 x thickness
24.4 = 15 x thickness
thickness = [tex]\frac{24.4}{15}[/tex] = 1.63cm
Fossils in the gobi desert helped scientists learn?
Answer:
dinosaurs laid eggs,sabretooths were carnivores, bats lived millions of years ago ,fossils of cynobacteria exist?
Explanation:
I NEED HELP ASAP
Types of Cells
1) I have a cell membrane?
PROKARYOTE
EUKARYOTE *******
BOTH
2)I have a nucleus *
PROKARYOTE*****
EUKARYOTE
BOTH
3)I am a bacteria *
PROKARYOTE
EUKARYOTE
BOTH
1) Both cells have a cell membrane.
2) A nucleus is present in only Eukaryote cells.
3) I'm pretty sure Prokaryote cells are bacteria.
Hope this helps!! :)
If 25.98 mL of 0.1180 M KOH reacts with 52.50 mL of CH3COOH solution, what is the molarity of the acid solution?
Answer:
Explanation:
We shall use the formula S₁V₁ = S₂V₂
S₁ = .1180 M , V₁ = 25.98 mL
S₂ = ? , V₂ = 52.50 mL
.1180 M x 25.98 = 52.50 x S₂
S₂ = .0584 M
Molarity of the acid solution = .0584 M .
The concentration of the acid solution is 0.058 M.
The equation of the reaction is;
CH3COOH(aq) + KOH(aq) -----> CH3COOK(aq) + H2O(l)
The following are known;
Concentration of base CB = 0.1180 M
Volume of base VB = 25.98 mL
Concentration of acid CA = ?
Volume of acid VA = 52.50 mL
Number of moles of acid NA = 1
Number of moles of base NB = 1
Using;
CAVA/CBVB =NA/NB
CAVANB = CBVBNA
CA= CBVBNA/VANB
CA = 0.1180 M × 25.98 mL × 1/52.50 mL × 1
CA = 0.058 M
Learn more: https://brainly.com/question/24381583
Which of the following particles combine to form molecules?
Compounds
Protons
Electrons
Atoms
Answer: i think its protons and electrons but it also might just be atoms because protons and electrons make atoms when there are also neutrons
Explanation:
if u trust urself do it
Study these images.
4 photos of clouds. 1: Sky covered with large, flat layers of blue, grey clouds. 2: A tall, fluffy cloud shaped like an anvil. 3: Round, puffy clouds in a blue sky. 4: Thin, wispy clouds high in the sky.
Which image shows a cumulonimbus cloud?
1
2
3
Answer:
3
Explanation:
I wish you the best, its three or 2
Answer:
2
Explanation:
Edge 2021
A solution of 400mg of optically active 2-butanol in 10 mL of water, placed in a 20 cm cell shows an optical rotation of 40o. What is the specific rotation of this compound?
Answer:
Specififc rotation [∝] = 0.5° mL/g.dm
Explanation:
Given that:
mass = 400 mg
volume = 10 mL
For a solution,
The Concentration = mass/volume
Concentration = 400/10
Concentration = 40 g/mL
The path length l = 20 cm = 2 dm
Observed rotation [∝] = + 40°
Specififc rotation [∝] = ∝/l × c
where;
l = path length
c = concentration
Specififc rotation [∝] = (40 / 2 × 40)
Specififc rotation [∝] = 0.5° mL/g.dm
Using the specific rotation formular, the specific rotation obtained for the compound ls 5°
Given the Parameters :
Observed rotation, [tex] \alpha = 40° [/tex] Path length, l = 20 cm = 2 dmConcentration, C
Concentration = mass × volume
Mass = 400 mg = 400 /1000 = 0.4g
Volume = 10 mL
Concentration = 0.4g × 10 mL = 4g/mL
The specific rotation formular, [tex] [\alpha] [/tex] is given by :
[tex] [\alpha] = \frac{\alpha_{observed}}{C \times l} [/tex]
[tex] [\alpha] = \frac{40°}{4 \times 2} = \frac{40°}{8} = 5° [/tex]
Therefore, the specific rotation of the compound ls 5°
Learn more :https://brainly.com/question/5963685?referrer=searchResults
) What would be the effect on the molarity of the NaOH solution if some of the water evaporated from the Florence flask after the NaOH solution was standardized with the KHP
Answer:
The effect is the increasing of the molar concentration.
Explanation:
When you standarize a solution of NaOH with KHP you are establish its molar concentration (That is the amount of moles of NaOH per liter of solution).
If you evaporated some water of the solution, you are increasing its concentration because volume is decreasing doing the amount of moles per liter increasing.
Consider the diagram below.
What does C represent?
A) enthalpy of reaction
B) activation energy
C) activated complex
D) energy of the reactants
Answer:
A) enthalpy of reaction
Explanation:
The region C signifies the enthalpy of reaction.
This diagram is the energy profile of an endothermic reaction. In such reaction, heat is absorbed from the surrounding. At the end of the reaction, the heat of product is lesser than that of the reactants.
Enthalpy changes are heat changes accompanying a physical and chemical change. An enthalpy is the difference between the sum of the heat contents of products and sum of the heat contents of reactants.it is indeed A) enthalpy of reaction
1.191 mol N2O3 is put into a 2.00 L flask at 25°C where it decomposes into NO2(g) and NO(g). What is the equilibrium constant (to 4 decimal places) if the reaction mixture contains 0.300 mol NO2 at equilibrium?
Answer:
K = 0.0505
Explanation:
Based on the equilibrium:
N2O3 ⇄ NO2 + NO
K, equilibrium constant, is defined as:
K = [NO2] [NO] / [N2O3]
Where [] are the equilibrium concentration of each species in the mixture.
The initial molarity of N2O3 is:
1.191mol / 2.00L = 0.5955M
In equilibrium, 0.5955M of N2O3 reacts producing X Molar of NO2 and X Molar of NO:
[N2O3] = 0.5955M - X
[NO2] = X
[NO] = X
As equilibrium concentration of NO2 is 0.300mol/2.00L = 0.15M; X = 0.15M:
[N2O3] = 0.5955M - 0.15M = 0.4455M
[NO2] = 0.15M
[NO] = 0.15M
And K is:
K = [0.15M] [0.15M] / [0.4455M]
K = 0.0505
How many Iron (Fe) atoms should be on the products side for the equation below to obey the Law of Conversation of Mass? 25 points
2
4
1
3
Answer:
infinite
Explanation:
How many hydrogen atoms are there in 1.15 g of methane (CH4)?
7. All physical forms of water (solid, liquid, and gas) make up the
a. atmosphere.
b. biosphere.
C. hydrosphere.
8. The living portion of the earth is contained within the
a. lithosphere.
b. biosphere.
C. hydrosphere.
9. The correct sequence of layers of the atmosphere from innermost to outermost is
a. troposphere--stratosphere--mesosphere--thermosphere.
b. mesosphere--stratosphere--thermosphere--troposphere.
c. thermosphere--stratosphere--mesosphere--troposphere.
10. Most of Earth's weather occurs in the
a. mesosphere.
b. troposphere.
C. stratosphere.
Answer:
C. Hydrosphere for 7
B. Biosphere for 8
Explanation: I am not sure about the rest of them.
In carbon dioxide (CO2), there are two oxygen atoms for each carbon atom. Each oxygen atom forms a double bond with carbon, so the molecule is formed by two double bonds.
Two double bonds means that the total number of electrons being shared in the molecule is
Answer:
The Answer is eight.
Explanation:
Sorry if it's too late and it doesn't help! But I hope you have a magnificent day! :3
Answer:
8
Explanation:
I had this question on my quiz and got it right.
Which particle is negatively charged?
A. proton
B. atom
C. neutron
D. electron
Answer:
D. electron
Explanation:
Electrons have a negative charge
Find the density of a liquid that has a mass of 24 grams and a volume of 6 ml.
Answer:
4
Explanation:
24/6 is 4.
Answer:
Mathematically: D = m/v. If you know what liquid you have, you can look up its density in a table. Once you know that, all you have to do to find the mass of the liquid is to measure its volume. Once you know density and volume, calculate mass using this relationship: mass = density • volume.
Explanation:
Explain what happened to the electrons in the elements when you exposed them to the flame. *please help
Explanation:
When you heat an atom, some of its electrons are "excited* to higher energy levels. When an electron drops from one level to a lower energy level, it emits a quantum of energy. ... The different mix of energy differences for each atom produces different colours. Each metal gives a characteristic flame emission spectrum.